This invention relates to a map data update method and to a navigation apparatus, and more particularly relates to a map data update method and navigation apparatus for performing compound updates of nationwide updated versions of map data using route-specific update data and nationwide update data.
A navigation apparatus reads map data from a CD-ROM, DVD, HDD, or other storage media according to the current position of a vehicle, generates map images, and draws maps on a display screen, as well as displaying a vehicle symbol at a fixed position on the display screen, and scrolling the displayed map according to the vehicle travel. Map data comprises (1) road layer information, comprising node data, road link data, intersection data, and similar; (2) background layer information, to display objects on the map; and, (3) character layer information, to display the names of cities, towns and villages, and other characters. Map images displayed on the display screen are generated based on the background layer information and character layer information; route search processing from a departure point to a destination, processing to display the route on a map and provide guidance, map-matching processing, and similar are performed based on the road layer information. In addition to the above, a navigation apparatus comprises POI (Point of Interest) display functions for displaying prescribed POI symbols on maps, map enlargement/reduction functions, map three-dimensional display functions, and various other functions.
Map data stored on recording media becomes out-of-date with the passage of time, due to new road construction and other modifications to topographic data, openings and closings of facilities, preparation of sites for housing, and for other reasons. Hence a method has been proposed in which map data is recorded onto a hard disk HDD or other map storage portion, and when there are modifications to map data, the map data on the hard disk HDD is overwritten with the latest map data. In this technology of the prior art, the user obtains the difference between the new map data and the old map data from a center by means of communication, or purchases an update DVD on which is recorded the difference between the new map data and the old map data, and updates the old map data on the hard disk HDD with the new map data. By this means, the new map data recorded on the hard disk HDD can be used in navigation control, and moreover a DVD player device for use in enjoying music or videos can also be used as a DVD player device for maps; in addition, music and videos can be enjoyed during navigation control.
FIG. 9 is a summary explanatory drawing of update DVD creation processing by an update data creation device.
Map data comprises numerous files, and so in the update data creation device (not shown), processing is performed to extract the differences, for each file, between the new map file NFL for the new version (Ver. 2) and the old map file OFL for the old version (Ver. 1), to create difference data files (update files) RNF1 to RNFN; thereafter, all the update files RNF1 to RNFN are combined to create the update data, and this update data is written to a DVD to create an update DVD.
(A) of FIG. 10 is a diagram explaining a method of creation, for each file, of difference data files (update files); the new map file NFL and old map file OFL are compared in byte units, a search is performed for data areas 1 to 3 in the old map file OFL which coincides with data areas 1′ to 3′ in the new map file NFL, and the leading addresses AD1 to AD3 and sizes S1 to S3 of the data areas 1 to 3 are determined as coincidence area identification data. Then, new map data A to D not coincides with the old map data, and the coincidence area identification data, are arranged in order to create the difference data file shown in (B) of FIG. 10. In (A) of FIG. 10, locations at which arrows indicate both are areas at which the data in the old file is the same as that in the new map file; unmatched data DLTM in the old map file OFL is discarded, and the unmatched data A to D in the new map file NFL is used as difference data.
In the example of (A) of FIG. 10, the difference data file is as shown in (B) of FIG. 10. That is, the difference data file comprises the following data.                New map file: New map data A        Old map file: Data identifying coincidence area 1 (leading address AD1, size S1)        New map file: New map data B        Old map file: Data identifying coincidence area 3 (leading address AD3, size S3)        New map file: New map data C        Old map file: Data identifying coincidence area 2 (leading address AD2, size S2)        New map file: New map data D        
If the difference data file sizes become too large, then there is the problem that time is required by the processing to create new map files from the old map files and the difference data files. Hence the applicants have proposed a method for reducing the sizes of difference data files. In the proposed method, (1) a new map is drawn by the new map data, (2) a replacement range is specified in the new map which has been drawn, (3) the map data portion of the replacement range is created as an additional file, (4) the map data portion of the replacement range is deleted from the old map data, (5) pseudo-new map data is created for use in incorporating the additional file into the old map data after deletion to create a difference data file (update file), and (6) the old map data and the pseudo-new map data are used to create difference data. By this means, only the locations necessary for navigation control, such as for example the map data portions for a newly opened route, can be provided as an additional file, and the size of the difference data file (update file) for the route can be made small.
(A) Principle of Update File Creation
FIG. 11 explains the principle of update file creation; the pseudo-new map data PNMP is created, and using the pseudo-new map data PNMP and the old map data OMP, update data is created.
The additional file creation portion 1 extracts from the new map data NMP the required locations (newly opened routes) and creates an additional file ADF. The additional file incorporation portion 2 creates pseudo-new map data PNMP for use in deleting the portion of map data for additional file incorporation from the old map data OMP, and incorporating the additional file ADF into the old map data after the map data deletion to create update data. The pseudo-new map data PNMP does not completely match the new map data NMP, but includes the necessary modifications (route modification portions). The update data creation portion 3 uses the old map data OMP and the pseudo-new map data PNMP to create an update DVD on which the update data RNM is recorded, by the method explained using FIG. 10.
FIG. 12 and FIG. 13 are figures explaining map data. As shown in (A) of FIG. 12, for each of various functions (DATA, FREEWAY, MAP, POI, RC, RG, STREET, TOLL, VICS), the map data is divided finely by level or area and created with a directory structure, and is recorded on recording media. Among the various functions, DATA is landmark data, junction map data and similar; FREEWAY is freeway data; MAP is map data; POI is POI (Point of Interest) information search data; RC is guidance route search data; and RG is route guidance data and similar.
The map data MAP is in a directory structure, and has seven levels extending from detailed maps (Level 00) to broad-area maps (Level 06); when the maps on each level are divided by a mesh, the map data MAP comprises the data file MP XXXX.mba for map display (data file for road shape display) for each mesh element, and the data files RF XXX.mba for background, character, and symbol display. In (A) of FIG. 12, a Level 06 map (a map of all of Japan) is divided into four mesh elements, and the data files for map display for the mesh elements are MP 000.mba to MP 0003.mba and RF 0000.mba to RF 0003.mba.
(B) in FIG. 12 shows that Level 01 is divided into five 1st mesh elements, and that one 1st mesh element is further divided into seven secondary mesh elements, with the data files for display of a prescribed secondary mesh element (2nd 0005) being MP 0000.mba and RF 0000.mba. From the above, the necessary map display data files MP 0000.mba and RF 0000.mba can be acquired by traversing in order the directory structure, from the Level 01 directory to the 1st3927 directory, and then to the 2nd0005 directory.
(A) of FIG. 13 is an example of the configuration of information search data POI, arranged by search item in a directory structure such that address hierarchical searches, address alphabetic-order searches, building searches, freeway route searches, facility searches, telephone number searches, and similar are possible. (B) of FIG. 13 is an example of the structure of freeway route search data FREEWAY; in the freeway route search directory FREEWAY are two child directories LIST and P_tree00 mba. P_Tree00 mba is a file which represents the search tree. In the directory LIST are directories List 000 to List 008 corresponding to nine regions (Hokkaido, Tohoku, Kanto, Kyushu, and similar); in the Hokkaido list directory List 000 are ten files P_list000.mba to P_list009.mba describing freeway routes.
FIG. 14 explains a method of creating and incorporating an additional file ADF which identifies road addition locations to be added to the old map data. The additional file creation portion 1 (FIG. 11) uses a prescribed new map file NFL, comprising addition locations, to draw a new map 5, and in addition uses the corresponding old map file OFL to draw the old map 6. Then, the additional file creation portion 1 specifies a replacement range 7, encompassing modified roads in the new map 5 thus drawn, and creates a map data portion within the replacement range as an additional file ADF. The additional file incorporation portion 2 deletes the map data portion (deletion portion) DLF within the replacement range 7 from the old map file OFL, and incorporates the additional file ADF into the old map file OFL′ after deletion to create a pseudo-new map file PNMF.
(B) Update Data Creation Device
FIG. 15 shows the configuration of the update data creation device 10, and is an example of creating update data and writing the data to a DVD. The map file input portion 11 inputs old map files OFL and new map files NFL (for example, the pseudo-new map files PNMF of FIG. 11) to the difference extraction processing portion 12. The difference extraction processing portion 12 determines, for each map file, the difference data between the old map file OFL and the new map file NFL, and based on the difference data creates a difference data file (update file), which is stored in the update data storage portion 13. At this time, the difference extraction processing portion 12 uses the procedure described below to update a serial number management file SNF held in memory 14 and stores the file in memory 14, as well as inputting this file to the update data storage portion 13.
The update data storage portion 13 stores each update file and the serial number management file SNF as update data, and inputs the update data to a DVD recorder 15 upon a request from the DVD recorder; the DVD recorder 15 writes the update data RNM and serial number management file SNF to a DVD 16 to create an update DVD.
(C) Navigation Apparatus
FIG. 16 shows the configuration of a navigation apparatus 20; the map storage portion (for example, a hard disk HDD) 21 stores map data for use in navigation in a file format, and the hard disk drive 22 reads map data from the hard disk 21 according to instructions from a navigation control device 23, and can write new map data to the hard disk. The DVD playback portion 24 reads update data RNM from an update DVD 16 and inputs the data to the navigation control device 23. The vehicle position detection portion 25 detects the vehicle position and inputs the position to the navigation control device 23. By this means, the navigation control device can control navigation using map data. The data input portion 26 is a touchscreen, remote control device or similar; various commands and data are input, and an external communication interface 27 communicates with external equipment via a portable telephone, the Internet, or other means. It is also possible to communicate with an external update data creation portion and acquire update data RNM, without reading update data RNM from an update DVD 16. The monitor device 28 displays maps for navigation, and displays operation menu screens as appropriate. The navigation voice guidance portion 29 notifies the user by voice of guidance details for approaching intersections (such as whether to turn left or right, the distance remaining to the intersection, and similar).
The navigation control device 23 executes navigation processing NAVI and map update processing MRNW in parallel under multitasking control; but because navigation processing is given higher priority than map update processing, the map update control is performed during free time when navigation control is not being performed, as shown in FIG. 17.
In map update processing, the navigation control device 23 uses update data (update files, serial number management file) read from an update DVD 16 to update map data (old map data) stored on the hard disk 21. Map update processing is performed using update data, in order from for example the north of Japan toward the south, that is, from Hokkaido toward Kyushu (nationwide update processing); when, during navigation processing, a map file for a region which has not been updated is requested, the nationwide update processing is temporarily interrupted, the map data for the region is updated (on-demand update processing), and after completion of on-demand update processing, the nationwide update processing is resumed, and navigation control is performed based on the new map files resulting from on-demand updating.
In update processing, the navigation control device 23 uses update files read from the update DVD 16 and old map files read from the hard disk 21 to create new map files, and the new map files are used to update old map files stored on the hard disk 21. The navigation control device 23 updates the serial numbers of updated map files to new serial numbers comprised by update files, explained below, without modifying the serial numbers of map files which have not been updated.
(E) Serial Numbers
Initially, consecutive serial numbers are assigned, in ascending order from 0, to each map file stored on the hard disk HDD 21 of the navigation apparatus 20. When performing map updates, the navigation apparatus 20 assigns to updated map files consecutive serial numbers in ascending order, starting from the next number after the largest serial number previously assigned, without modifying the serial numbers of map files which have not been updated.
FIG. 18 explains the serial numbers of map files; to simplify the explanation, it is assumed that the number of map files is 100, but in actuality approximately 100,000 files exist.
Initially, as shown in (A) of FIG. 18, serial numbers 0, 1, 2, . . . , 99 are assigned in order to the 100 map files MF00 to MF99. In this state, if update files RNF01 and RNF99 are used to update the map files MF01 and MF99 with serial numbers 1 and 99, as in (B) of FIG. 18, then after updating the serial numbers of the new map files are as shown in (C) of FIG. 18. That is, the serial numbers of map files which have not been updated are not modified, and the serial numbers of the updated map files MF01 and MF99 are modified, assigning the consecutive ascending serial numbers 100 and 101, which are next after the largest serial number (=99) assigned up to that time.
(F) Serial Number Management File
FIG. 19 explains a serial number management file SNF created by the update data creation device. The difference extraction processing portion 12 (see FIG. 15) of the update data creation device 10 writes a “valid” bit (“1”) at bit positions corresponding to the serial numbers 100 and 101 of the new map files, as shown in FIG. 19, and writes an “invalid” bit (“0”) at bit positions corresponding to the serial number positions 1 and 99 of the pre-update map files, to create the serial number management file SNF.
The serial number management file SNF is a file of size N bytes. The bit positions of each byte from the leading byte to the Nth byte are positions of serial numbers, and a “1” is recorded in bit positions corresponding to the serial numbers of map files. FIG. 15 shows a 256 kilobyte serial number management file SNF. Because eight serial numbers can be represented by one byte, the last bit of the 256 kilobyte file is a position corresponding to serial number 2,097,152 (=256×1024×8).
As explained below, the serial numbers and serial number management file SNF can be used to determine whether or not map files stored on the hard disk are map files which need be overwritten or whether or not the map files stored on the hard disk are map files which have been updated.
(G) Update Data Creation Processing
FIG. 20 explains update data creation processing by the update data creation device 10.
As shown in (A) of FIG. 20, the number of map files is assumed to be 100, and initial serial numbers for the 100 map files are 0 to 99. As shown in (B), “valid” bits (“1”) are written at bit positions equivalent to the serial numbers 0 to 99 of the serial number management file SNF.
The difference extraction processing portion 12 of the update data creation device 10 compares the old map files MP00 to MP99 with the new map files MP00′ to MP99′. Because there are differences between the old map file MP01 and the new map file MP01′ and between the old map file MP99 and the new map file MP99′, the difference extraction processing portion 12 first determines difference data between the old map file MP01 and the new map file MP01′, and based on the difference data and new serial numbers, creates an update file RNF01. However, the difference extraction processing portion 12 writes an “invalid” bit (“0”) at the bit position equivalent to the serial number 1 in the serial number management file SNF, as shown in (C), writes a “valid” bit (“1”) at the bit position equivalent to the next serial number 100 after the largest serial number (=99) assigned up to that time, and makes 100 a new serial number.
Next, the difference extraction processing portion 12 determines difference data between the old map file MP99 and the new map file MP99′, and based on the difference data and new serial numbers, creates the update file RNF99. Here, as indicated in (D), the difference extraction processing portion 12 writes an “invalid” bit (“0”) at the bit position equivalent to the serial number 99 in the serial number management file SNF, writes a “valid” bit (“1”) at the bit position equivalent to the new serial number 101 which is next after the largest serial number (=100) assigned up till that time, and makes 101 a new serial number. Through the above processing, creation of update files and updating of the serial number management file SNF are completed.
Thereafter, the update data creation device 10 inputs the above-described serial number management file SNF and map update files RNF01 and RNF99 into the navigation apparatus 20, as update data. When updating old map files using update files, the navigation apparatus 20 assigns the new serial numbers held in the update files RNF01 and RNF99 as the serial numbers of the updated map files. Hence the navigation apparatus 20 can refer to the serial number management file SNF stored in the storage portion 23a (see FIG. 16), and by determining whether the serial number position of a map file of interest is set to valid or invalid, can judge whether the map file has been updated.
(H) Background Updates
When navigation processing and map update processing are performed in parallel by means of multitasking processing, there are cases in which map files necessary for navigation control have not yet been updated. In such cases, it is convenient to be able to give priority to updating of these map files, and to use the updated new map files in navigation control. FIG. 21 shows the flow of such update processing (background update processing).
The navigation control device 23 (FIG. 16) reads a map file necessary for navigation control (step 101), and extracts the serial number of the map file (step 102). Then, the navigation control device 23 refers to the serial number management file SNF to check whether “valid” bits (“1”) is entered in the position of the serial number of the map file (step 103). If a “1” is entered, the file has been updated; if a “0” is entered, the file has not been updated.
If the file has been updated, the map file which has been read is used to execute navigation control (step 104). If on the other hand the file has not been updated, the update processing being performed in parallel through multitasking control (nationwide update processing) is interrupted (step 105), and on-demand update processing is executed (step 106).
In on-demand update processing, an update file needed to update the map file read in step 101 is read from the update DVD 16, the update file is used to create a new map file (step 106a), and a new serial number is assigned to the new map file (step 106b). Then, the old map file on the hard disk 21 is overwritten with the new map file, to complete the on-demand update processing (step 106c), and the nationwide update processing which had been interrupted is resumed (step 107).
The navigation control device 23 then uses the new map files updated in step 106 to execute navigation control (step 108).
By means of background update processing, even when map files necessary for navigation control have not yet been updated, the navigation control device 23 gives priority to updating of these map files, and the updated new map files can be used in navigation control, so that new map files can always be used in navigation control.
Further, the navigation control device 23 assigns serial numbers to map files, and by referring to the serial number management file based on these serial numbers can easily determine whether a map file stored in the map storage portion has been updated or not, so that background update processing can easily be accomplished.
(I) Update Data
FIG. 22 to FIG. 25 are diagrams explaining update data. As shown in (A) of FIG. 22, the update data which is difference between the old map and new map is indicated by “DIFFERENCE” to which function directories (DATA, FREEWAY, MAP, POI, RC, RG, STREET, TOLL, VICS) and an Index.dif file are connected and files for updating are connected to each function direction. The Index.dif file identifies (1) the version numbers before and after updating, (2) the total number of update files necessary for updating, and (3) the number of function directories to be updated.
Update files are specified for each function by a directory structure. (B) of FIG. 22 explains the directory structure of the function RG (route guidance data); the directories UP000 and Info0000.dif are present in the function directory RG. UP0000 is a directory used for update data entity files (UP000.dif to UP002.dif), and Info0000.dif is a directory with a plurality of lower-level difference update correspondence records #0 to #N.
As shown in (A) of FIG. 23, a difference update correspondence record has the following information:
(1) processing state (indicating whether directories below the directory of interest have been processed),
(2) directory name of the directory of interest,
(3) number of subdirectories (lower-level directories),
(4) number of update files existing in the directory of interest,
(5) difference update correspondence record numbers corresponding to subdirectories; and,
(6) difference update information record numbers corresponding to update files in the directory of interest.
Using the directory structure in (B) of FIG. 23 as an example, the directory of interest is MBA¥RG¥Level 01, and so the directory name is “Level 01”. The number of subdirectories is 3, and the number of update files is 0. Because there are three subdirectories, the difference update correspondence record numbers #X (1st 3622), #X+1 (1st 3623), and #X+2 (1st 3624) of the three subdirectories are identified. However, because the number of update files is 0, no difference update information record numbers are identified.
(A) and (B) in FIG. 24 are another example of a difference update correspondence record, in which the number of subdirectories is 0 and the number of update files is 2; the directory name is “Level 01”. Because the number of subdirectories is zero, no difference update correspondence record numbers are identified. However, because the number of update files is two, two difference update information record numbers (identifying update files), 1st 3622 and 1st 3623, are entered.
FIG. 25 is an example of a difference update information record number identifying an update file, and having the following information:
(1) processing state (whether the update file of interest has been processed or not),
(2) file name of the update file of interest (RG0000.mba),
(3) raw data flag (whether the update file is a file based on a new map file, or is a file based on difference data),
(4) file number for the update data entity file,
(5) offset from the beginning of the update data entity file, and
(6) update data size.
If the update entity file indicated by the update data entity file number has the raw data flag set to on, then the file is a new map file; if the raw data flag is off, then the file is a difference data file (update file).
By means of the above proposed method, various update data for newly opened routes is prepared in advance in an update data creation device, and update data requested by a navigation apparatus is provided; in the navigation apparatus, operation is possible such that old map data stored on a hard disk HDD is updated using the update data. FIG. 26 explains in summary this operation.
The update data is classified into update data common to all users for a nationwide updated version (referred to as nationwide update data) 31, and update data for each route-specific update version, in update performed individually by users (referred to as route-specific update data) 32a, 32b, . . . , and these nationwide update data and route-specific update data are created. The update data 31, 32a, 32b, . . . are always created based on the nationwide updated version map data (VER1) 30, and, when performing route-specific updates, is created route-specific update data comprising all routes newly opened from the time of release of the nationwide updated version (VER1) until the time of the route-specific update. For example, when, after release of nationwide updated version map data (VER1) 30, routes A and B are newly opened in the order route A→route B, route-specific update data is prepared in the following manner. That is, the following data is created and prepared in a center server (update data creation device):
When route A is newly opened: Route-specific update data 32a for route A to update the nationwide updated version (VER1) 30
When route B is newly opened: Route-specific update data 32b for routes (A+B) to update the nationwide updated version (VER1) 30
. . .
At time of release of a new nationwide updated version (VER2) 35: Nationwide update data 31 for a nationwide updated version (VER2) 35 to update the nationwide updated version (VER1) 30
In this state, if the vehicle navigation apparatus CNV acquires the update data 32a for route A from the server via a wireless terminal MS and updates the map data stored on the hard disk HDD, the map data is updated to a new map (VER1+route A) 33 with the map data of route A added. Similarly, if the navigation apparatus CNV acquires the update data 32b for routes (A+B) from the server via the wireless terminal MS and updates the map data stored on the hard disk HDD, the map data is updated to a new map (VER1+route A+route B) 34 with the map data for route A and route B added. Further, if all update data 31 is acquired, either by communication or through a purchased DVD, and the map data stored on the hard disk HDD is updated, then the map data is updated to the nationwide updated version of the map data (VER2) 35.
However, as explained above, update data is always created based on the nationwide updated version (VER1) 30. Hence prior to updating map data stored on the hard disk using update data, it is necessary to store data which is needed to restore this nationwide updated version (VER1) 30. The data needed to restore this nationwide updated version (VER1) 30 is pre-update map files.
FIG. 27 explains map update processing by the navigation apparatus; prior to using route-specific update data 32a (FIG. 26) to update map data of the nationwide updated version (VER1) 30 (comprising numerous map files) stored on the hard disk HDD of the navigation apparatus, the pre-update map files needed to restore the nationwide updated version (VER1) are stored in a free area of the hard disk HDD. For example, a “-” is appended to the file names of the map files of the nationwide updated version (VER1) to create and store the pre-update map files as shown in (A) of FIG. 27 (S101), and then the map files are updated using route-specific the update data 32a (S102).
Then, when the above-described updated map data is to again be updated using the route-specific update data 32b, the previously updated map files are deleted from the map data updated by the route-specific update data 32a as shown in (B) of FIG. 27 (S103). The previously updated map files have the same file names as the pre-update map files stored with a “-” appended. Then, the “-” appended to the file names of the pre-update map files which have been stored is deleted, and the map data for the nationwide updated version (VER1) 30 is restored (S104). After restoration, the procedure explained in (A) of FIG. 27 is used to perform update processing. When map data which has once been updated is to be updated using nationwide update data 31, a similar procedure is used, so that after restoring the nationwide updated version (VER1) 30, the map data is updated to the new nationwide updated version map data (VER2) 35.
FIG. 28 explains the interface between a center server (update data creation device) and navigation apparatus, when differentially updating map data using route-specific update data for all routes newly opened between the time of release of the nationwide updated version map data (VER1) and a prescribed date. Upon a request for update data from the navigation apparatus, the center server displays on a display device of the navigation apparatus a “latest map confirmation screen”, shown in (A) of FIG. 28, to specify the date until which update data is required. When the user selects a prescribed date at this screen, the center server displays the screen shown in (B) of FIG. 28, and upon selection of “YES” downloads the route-specific update data for the routes. If “NO” is selected, the “latest map confirmation screen” of (A) is again displayed.
However, when the latest nationwide updated version (VER2) is released, and thereafter prescribed route-specific update data is created, often the navigation apparatus must perform a nationwide update to the latest nationwide updated version (VER2) in the background while performing navigation control. In order for the user to acquire the prescribed route-specific update data and update the map data in the navigation apparatus in such background updating, after updating a nationwide updated version (VER1) to the latest nationwide updated version (VER2) as shown in (A) of FIG. 29, the route-specific update data 36 is used to update the nationwide updated version (VER2) to new maps (VER2+route A) 37, as shown in (B) of FIG. 29. However, before completing the nationwide update in this method, even if route-specific update data is acquired, if the nationwide update is not entirely completed, then the updated map data cannot be used with the route-specific update data. The nationwide update is performed through background updating (updating during free time when navigation control is not performed), but because this processing requires a number of hours of processing time, navigation control using map data which reflects the desired route-specific updates is delayed.
Further, there are cases in which map data which has once been updated using route-specific update data is to be updated to the latest nationwide updated version (VER2), or is to be updated using other route-specific update data. In such cases, as shown in (A) of FIG. 30, after returning the updated map data (VER1+route A) 33 to the nationwide updated version (VER1) 30, the nationwide update data 31 must be used to perform an update to the latest nationwide updated version (VER2) 35 ((B) in FIG. 30).
Or, as shown in (A) of FIG. 30, after returning the updated map data (VER1+route A) 33 to the nationwide updated version (VER1) 30, route-specific update data 32b must be used to update to updated map data (VER1+route A+route B) 34, as shown in (C) of FIG. 30. That is, when performing the next update after having performed a route-specific update, if the data is not first completely returned to the state of the nationwide updated version, the desired navigation control based on map data is not possible.
In one method of the prior art, when map information for navigation is updated, update data is downloaded immediately from an information provision center to a navigation apparatus or is installed (Japanese Patent Publication JP2004-12319A). In this method of the prior art, update data is provided to the navigation apparatus via communication, but route-specific update data is not used to update maps. In particular, navigation control cannot be performed while performing an update using desired route-specific data even when nationwide updating is not completed.